The primary objectives of Core B are to support development of study design, management of data collection, and performance of statistical analyses to validly test the research hypotheses and questions under investigation in the Biology of the Prostate Cancer Prevention Trial (PCPT) Program Project. Core B will play a pivotal role in the Program Project, interacting with every Project and Core. In the study-design phase, Core B will assist investigators in formulating studies that can feasibly address the questions of scientific interest, are amenable to analysis by statistical and data-mining methods, and will ultimately yield statistically valid and interpretable results. An equally important role for Core B will be database design and coordination of the selection, shipping, and accumulation of results from analyses on serum, white blood cell and tissue samples. This Core will be responsible for managing the overall data infrastructure for all Projects and Cores involved in this program project. This includes maintaining the clinical database, electronic transfer of lab data over secure pathways, tracking samples and verifying that the necessary material is sent to the correct laboratory at the correct time, and ensuring the security and confidentiality of all data. This core will also provide uniform high-quality support for all statistical analyses, using both standard and specialized biostatistical methods. The overall goal of this program project is to identify factors that are associated with prostate cancer and high grade prostate cancer, and to identify factors that may predict who may and may not respond to finasteride treatment for the prevention of prostate cancer. The revised Project addresses all reviewer concerns, including those for justifying expected effect sizes and clarifying our approach to multiple testing of polymorphisms.